Place a wok or wide frying pan over high heat until hot.
Add the oil, swirling to coat the sides.
Add the garlic and chiles and cook, stirring, until fragrant, about 10 seconds.
Add the pork and stir-fry until it is no longer pink, about 2 1/2 minutes.
Add the basil and green onions and stir-fry for 30 seconds.
Add the broth, fish sauce, and sugar; mix well and add the cornstarch solution.
Cook, stirring, until the sauce boils and thickens.